Customize the appearance of simple pillars in your tibble subclass

Gain full control over the appearance of the pillars of your tibble subclass in its body. This method is intended for implementers of subclasses of the "tbl" class. Users will rarely need them.

Usage

ctl_new_pillar(controller, x, width, ..., title = NULL)

ctl_new_rowid_pillar(controller, x, width, ..., title = NULL, type = NULL)

Arguments

controller

The object of class "tbl" currently printed.

x

A simple (one-dimensional) vector.

width

The available width, can be a vector for multiple tiers.

...

These dots are for future extensions and must be empty.

title

The title, derived from the name of the column in the data.

type

String for specifying a row ID type. Current values in use are NULL and "*".

Details

ctl_new_pillar() is called to construct pillars for regular (one-dimensional) vectors. The default implementation returns an object constructed with pillar(). Extend this method to modify the pillar components returned from the default implementation. Override this method to completely change the appearance of the pillars. Components are created with new_pillar_component() or pillar_component(). In order to customize printing of row IDs, a method can be supplied for the ctl_new_rowid_pillar() generic.

All components must be of the same height. This restriction may be levied in the future.

Implementations should return NULL if none of the data fits the available width.

See also

See ctl_new_pillar_list() for creating pillar objects for compound columns: packed data frames, matrices, or arrays.

Examples

# Create pillar objects
ctl_new_pillar(
  palmerpenguins::penguins,
  palmerpenguins::penguins$species[1:3],
  width = 60
)
#> <pillar>
#> <fct> 
#> Adelie
#> Adelie
#> Adelie

ctl_new_pillar(
  palmerpenguins::penguins,
  palmerpenguins::penguins$bill_length_mm[1:3],
  width = 60
)
#> <pillar>
#> <dbl>
#>  39.1
#>  39.5
#>  40.3

# Customize output
lines <- function(char = "-") {
  stopifnot(nchar(char) == 1)
  structure(char, class = "lines")
}

format.lines <- function(x, width, ...) {
  paste(rep(x, width), collapse = "")
}

ctl_new_pillar.line_tbl <- function(controller, x, width, ...) {
  out <- NextMethod()
  new_pillar(list(
    title = out$title,
    type = out$type,
    lines = new_pillar_component(list(lines("=")), width = 1),
    data = out$data
  ))
}

ctl_new_rowid_pillar.line_tbl <- function(controller, x, width, ...) {
  out <- NextMethod()
  new_pillar(
    list(
      title = out$title,
      type = out$type,
      lines = new_pillar_component(list(lines("=")), width = 1),
      data = out$data
    ),
    width = as.integer(floor(log10(max(nrow(x), 1))) + 1)
  )
}

vctrs::new_data_frame(
  list(a = 1:3, b = letters[1:3]),
  class = c("line_tbl", "tbl")
)
#> # A data frame: 3 × 2
#>       a b    
#>   <int> <chr>
#> 1     1 a    
#> 2     2 b    
#> 3     3 c    

ctl_new_rowid_pillar.roman_tbl <- function(controller, x, width, ...) {
  out <- NextMethod()
  rowid <- utils::as.roman(seq_len(nrow(x)))
  width <- max(nchar(as.character(rowid)))
  new_pillar(
    list(
      title = out$title,
      type = out$type,
      data = pillar_component(
        new_pillar_shaft(list(row_ids = rowid),
          width = width,
          class = "pillar_rif_shaft"
        )
      )
    ),
    width = width
  )
}

vctrs::new_data_frame(
  list(a = 1:3, b = letters[1:3]),
  class = c("roman_tbl", "tbl")
)
#> # A data frame: 3 × 2
#>       a b    
#>   <int> <chr>
#> 1     1 a    
#> 2     2 b    
#> 3     3 c